Simulator vs device; Deferring System Gestures

Hi, I have a full screen iOS game. In the Simulator, preferredScreenEdgesDeferringSystemGestures works well to prevent a drag down from the top of the full-screen play area from immediately opening the Notification Center. (You got a tab, and had to swipe down on it.) But at least on my device, when testing, unlike in Simulator, Notification Center opens immediately when I swipe down from the top. Any suggestions?

Simulator vs device; Deferring System Gestures
 
 
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